Articulating surgical instruments

ABSTRACT

A surgical instrument and its method of use are disclosed. In one embodiment, the surgical instrument may include a handle and an elongated shaft assembly extending distally from the handle. The elongated shaft assembly may include an articulable portion with an articulation direction. The elongated shaft assembly may also include a tubular member with a flexible portion with a preferential bending direction and a direction of bending resistance. The tubular member may permit articulation of the elongated shaft assembly when the preferential bending direction is aligned with the articulation direction.

RELATED APPLICATIONS

This application is a divisional application and claims the benefitunder 35 U.S.C. §120 of U.S. application Ser. No. 13/827,254, filed onMar. 14, 2013, which is herein incorporated by reference in itsentirety.

FIELD

Articulating surgical instruments.

BACKGROUND

A surgical mesh fabric or other prosthetic repair fabric may be used tosurgically repair a hernia. The prosthetic repair fabric is typicallyplaced in an open procedure or laparoscopically. Oftentimes a surgicalinstrument is used to secure the repair fabric in place by deploying oneor more fasteners from a distal end of the surgical instrument throughthe prosthetic repair fabric and into the underlying tissue. However, asurgical instrument that includes a rigid elongated shaft assembly fordeploying the fasteners may have a limited range of motion within thesurgical field. Consequently, many surgical instruments include at leastone articulable portion along the elongated shaft assembly to facilitatethe orientation and placement of fasteners within the surgical field.

SUMMARY

In one embodiment, a surgical instrument includes a handle and anelongated shaft assembly extending distally from the handle. Theelongated shaft assembly includes an articulable portion with anarticulation direction. The elongated shaft assembly also includes atubular member with a flexible portion with a preferential bendingdirection and a direction of bending resistance. The tubular memberpermits articulation of the elongated shaft assembly when thepreferential bending direction is aligned with the articulationdirection.

In another embodiment, a surgical instrument includes a handle and anelongated shaft assembly extending distally from the handle. Theelongated shaft assembly includes a first tubular member including afirst flexible portion with a first preferential bending direction, asecond tubular member including a second flexible portion with a secondpreferential bending direction, and a third tubular member including athird flexible portion with a third preferential bending direction and adirection of bending resistance. The first tubular member, the secondtubular member, and the third tubular member are coaxially located. Thefirst tubular member and the second tubular member are axially fixedrelative to one another at a position distal from the first flexibleportion and the second flexible portion. The third tubular member isdisplaceable relative to the first tubular member and the second tubularmember.

In yet another embodiment, a surgical instrument includes a handle andan elongated shaft assembly extending distally from the handle. Theelongated shaft assembly includes a first tubular member including afirst flexible portion with a first spine, a second tubular memberincluding a second flexible portion with a second spine, and a thirdtubular member including a third flexible portion with a third spine anda fourth spine. The first tubular member, the second tubular member, andthe third tubular member are coaxially located. The first tubular memberand the second tubular member are also axially fixed relative to oneanother at a position distal from the first flexible portion and thesecond flexible portion. Additionally, the third tubular member isdisplaceable relative to the first tubular member and the second tubularmember.

In another embodiment, a surgical instrument includes a handle and anelongated shaft assembly extending distally from the handle. Theelongated shaft assembly includes a first tubular member including afirst flexible portion with a first spine and a second tubular memberincluding a second flexible portion with a second spine and a thirdspine. The first tubular member and the second tubular member arecoaxially located. Additionally, the first tubular member and the secondtubular member are axially fixed relative to one another at a positiondistal from the first flexible portion and the second flexible portion.The second tubular member is also rotatable relative to the firsttubular member.

In yet another embodiment, a method of operating a surgical instrumentincludes: providing: a handle; an elongated shaft assembly extendingdistally from the handle, wherein the elongated shaft assembly includesan articulable portion with an articulation direction, and wherein theelongated shaft assembly includes a tubular member with a flexibleportion with a preferential bending direction and a direction of bendingresistance; and displacing the tubular member to selectively align thepreferential bending direction of the tubular member with thearticulation direction of the elongated shaft assembly to permitarticulation of the elongated shaft assembly.

It should be appreciated that the foregoing concepts, and additionalconcepts discussed below, may be arranged in any suitable combination,as the present disclosure is not limited in this respect. Further, theforegoing and other aspects, embodiments, and features of the presentteachings can be more fully understood from the following description inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings are not intended to be drawn to scale. In thedrawings, each identical or nearly identical component that isillustrated in various figures may be represented by a like numeral. Forpurposes of clarity, not every component may be labeled in everydrawing. In the drawings:

FIG. 1 is a schematic representation of an articulable surgicalinstrument;

FIG. 2 is a schematic representation of an articulable portion of anelongated shaft assembly;

FIG. 3A is a schematic side view of the inner tubular member;

FIG. 3B is a schematic side view of the inner tubular member of FIG. 3Arotated 90°;

FIG. 4A is a schematic side view of the intermediate tubular member;

FIG. 4B is a schematic side view of the intermediate tubular member ofFIG. 4A rotated 90°;

FIG. 5A is a schematic side view of the outer tubular member;

FIG. 5B is a schematic side view of the outer tubular member of FIG. 5Arotated 90°;

FIG. 6A is a schematic perspective view of the inner and intermediatetubular members in an unarticulated position;

FIG. 6B is a schematic perspective view of the inner and intermediatetubular members in an articulated position;

FIG. 7A is a schematic perspective view of the distal portion of theinner and intermediate tubular members;

FIG. 7B is a cross-sectional view of the inner and intermediate tubularmembers depicted in FIG. 7A;

FIG. 8 is an exploded schematic representation of the tubular members inthe articulable configuration;

FIG. 9 is a schematic cross-sectional view of the tubular members in thearticulable configuration;

FIG. 10 is an exploded schematic representation of the tubular membersin the locked configuration;

FIG. 11 is a schematic cross-sectional view of the tubular members inthe locked configuration; and

FIG. 12 is a schematic representation of the interior of the surgicalinstrument handle.

DETAILED DESCRIPTION

The inventors have recognized that it may be desirable to selectivelypermit or prevent the articulation of a surgical instrument inparticular instances. For example, it may be desirable to prevent thearticulation of a surgical instrument during the insertion andextraction of the surgical instrument into a surgical field as mightoccur during laparoscopic surgery.

In one embodiment, an elongated shaft assembly extends distally from thehandle of a surgical instrument and includes an articulable portion. Thearticulable portion of the elongated shaft assembly may articulate in atleast one direction between a first position, such as an unarticulatedposition, and a second position, such as a fully articulated position.In addition to the elongated shaft assembly, the surgical instrument mayinclude a rotatable tubular member with a flexible portion that isassociated with the articulable portion of the elongated shaft assembly.For example, the flexible portion of the tubular member may be axiallyaligned and at least partially coextensive with the articulable portionof the elongated shaft assembly. The flexible portion of the tubularmember may have a preferential bending direction as well as a directionof bending resistance. Rotation of the tubular member relative to thearticulable portion of the elongated shaft assembly may selectivelyalign either the preferential bending direction or the direction ofbending resistance of the flexible portion with the articulationdirection of the elongated shaft assembly. When the preferential bendingdirection of the flexible portion is aligned with the articulationdirection, the elongated shaft assembly may articulate. In contrast,when the direction of bending resistance of the flexible portion isaligned with the articulation direction, articulation of the elongatedshaft assembly may be prevented. Thus, rotation of the tubular memberrelative to the articulable portion of the elongated shaft assembly mayselectively permit or prevent articulation of the surgical instrument.

The various tubular members associated with the articulation lockingmechanism as well as the articulable portion of the elongated shaftassembly may be constructed and arranged in any number of ways toprovide one or more preferential bending directions and/or directions ofbending resistance. For example, in one embodiment, a tubular member mayinclude one or more weakened sections along one or more sides of thetubular member to provide one or more preferential bending directionsand directions of bending resistance. These weakened sections may beprovided by: an appropriate pattern of slots, cuts, and/or spines;composite structures of flexible and rigid materials; combinations ofthe above; or any other appropriate construction. Alternatively, in someembodiments, a tubular member might include a plurality ofinterconnected segments to form the flexible portion. Theseinterconnected segments could be constructed and arranged to permitmovement in one or more directions, corresponding to preferentialbending directions and resist movement in one or more directionscorresponding to directions of bending resistance. For example, theinterconnected segments may only have a single axis of rotation due tothe use of pin joints in the same orientations to connect the segmentsthus permitting pivoting of adjacent interconnected segments in onedirection and resisting all other directions of movement.

While several possible embodiments related to the construction of thearticulable elongated shaft assembly are described herein, it should beunderstood that the current disclosure is not limited to only thedescribed embodiments. For example, the articulable portion of theelongated shaft assembly may be constructed and arranged in anyappropriate fashion to provide articulation in a desired direction.Further, while a specific type of articulation mechanism using tubularmembers with offset neutral bending axes is described, the currentlydisclosed articulation locking mechanism may be used with anyappropriate method of articulating an elongated shaft assembly. Forexample the articulable portion of the elongated shaft assembly may bearticulated using: one or more control wires, ribbons, or slatsassociated with the articulable portion; prestressed members andretractable sheaths, rigid linkages associated with pivot joints; or anyother appropriate structure capable of articulating the articulableportion.

In addition to the above, while several patterns of slots and spines aredisclosed regarding the flexible portions of the tubular members, itshould be understood that other patterns of slots and spines are alsopossible. For example, the flexible portions of the tubular memberscorresponding to the articulable portion of the elongated shaft assemblymay be constructed and arranged in any appropriate fashion such that theflexible portion preferentially bends in at least one direction andprovides an increased resistance to bending in at least one otherdirection.

For the sake of clarity, the currently disclosed embodiments discussedbelow in regards to the figures are directed to a laparoscopic devicefor deploying one or more fasteners. However, the current disclosure isnot limited to laparoscopic devices for deploying one or more fasteners.Instead, the disclosed articulation locking mechanisms could be used inany appropriate surgical instrument including an articulable portion.For example, an articulation locking mechanism, as disclosed herein,could be incorporated into an endoscopic device, a borescopic device, acatheter, a surgical instrument for use in “open” procedures, or anyother appropriate surgical instrument. Further, the disclosed surgicalinstruments may include any appropriate end effector and are not limitedto the deployment of fasteners. However, in those embodiments includingfasteners, the instrument including the articulation locking mechanismmay be loaded with one or more fasteners, or it may be constructed toallow the user to load the instrument with one or more fasteners. Inaddition, disclosed embodiments that include fasteners are describedwith regards to a generic fastener. Consequently, it should also beunderstood that any appropriate fastener might be used with thecurrently disclosed articulation locking mechanisms including a tack, aclip, a staple, a pin, a tissue anchor, a bone anchor, or any otherappropriate type of fastener.

Turning now to the figures, specific embodiments of an articulationlocking mechanism incorporated into a surgical instrument are described.

FIG. 1 presents one embodiment of a surgical instrument 2. The surgicalinstrument includes a handle 4 and an elongated shaft assembly 6extending distally from the handle 4. In addition to fasteners beingdeployed from a distal end of the elongated shaft assembly 6, theelongated shaft assembly may include an articulable portion 8.Articulation of the articulable portion 8 may be controlled by anarticulation control 10 which may be moved between one or more positionsto shift articulable portion 8 to a desired articulation angle. Thesurgical instrument 2 may also include a trigger 12 for actuating afastener deployment system 210 to deploy a fastener, see FIG. 12.

The articulable portion 8 depicted in FIG. 1 may be shifted between afirst position, such as an unarticulated (i.e. straight) position, andsecond position, such as a fully articulated position, using thearticulation control 10. Depending on the embodiment, the articulableportion 8 may be shifted to one or more preselected articulation angles,or the articulable portion 8 may be adjusted to one or more arbitrary(i.e. not preselected) articulation angles. The articulable portion 8may be articulated in at least a first direction. Embodiments in whichthe articulable portion articulates in at least a second direction arealso envisioned. For example, the articulable portion 8 may bearticulated in a first direction corresponding to an articulation anglegreater than approximately 0° and in a second direction corresponding toan articulation angle less than approximately 0°. Alternatively, or inaddition to the above, the articulable portion 8 might be articulatedabout two different axes (e.g. articulation in the horizontal directionand the vertical direction) such that it articulates in at least twodirections.

In some embodiments, it may be desirable to rotate the elongated shaftassembly 6 to facilitate positioning of the distal tip. One suchembodiment is depicted in FIGS. 1 and 12. The rotation of the elongatedshaft assembly 6 may be provided in any appropriate manner. For example,the elongated shaft assembly 6 may simply be adapted to be rotatable toat least a portion of the handle 4. Alternatively, a portion of thehandle 4 including the elongated shaft assembly 6 may be rotatablerelative to a another portion of the handle 4, such as the portionincluding the grip. One such embodiment is depicted in FIG. 1. In thedepicted embodiment, the surgical instrument 2 includes a first handleportion 16 and a second handle portion 18 including the elongated shaftassembly 6. The first and second handle portions 16 and 18 may beconstructed and arranged in any appropriate fashion to be rotatablerelative to one another. It should be understood that while a surgicalinstrument including a rotatable elongated shaft assembly 6 or handle 4is depicted in the figures, a surgical instrument including a unitaryhandle and/or an elongated shaft assembly 6 that is stationary relativeto the handle are also possible as the current disclosure is not limitedin this manner.

In certain applications, it may be advantageous to include a distalrigid straight portion 12 that is distally located from the articulableportion 8. The rigid straight portion 12 may include a number offeatures to aid in the deployment of fasteners from the distal end ofthe elongated shaft assembly 6. For example, the distal rigid straightportion 12 may include fastener retaining elements such as tabs toretain a distal most fastener in a fastener deployment position prior toactuation of the surgical instrument. Additionally, without wishing tobe bound by theory, when a driveshaft of a fastener deployment systemapplies a force to a fastener as it goes around an articulated portionof the elongated shaft assembly, the force applied by the drive shaft tothe head of the fastener may not be fully aligned with the deploymentdirection of the associated fastener. Thus, it may be desirable toinclude the distal rigid straight portion 12 to provide a straightportion of the elongated shaft assembly with a sufficient lengthaccommodate a fastener and to permit the actuation force from thefastener deployment system to be applied to that fastener in the samedirection as the fastener deployment direction. Without wishing thebound by theory, this may result in reduced actuation forces required todeploy a fastener from the surgical instrument. While a surgicalinstrument 2 including a distal rigid straight portion 12 has beendescribed herein, and depicted in figures, it should also be understoodthat embodiments are envisioned in which the articulable portion 8extends all the way to the distal end of the elongated shaft assembly 6such that the surgical instrument does not include a distal rigidstraight portion.

FIG. 2 depicts an enlarged view of the distal end of the elongated shaftassembly 6 of FIG. 1 including the articulable section 8. In thedepicted embodiment, the elongated shaft assembly 6 includes coaxiallyaligned first, second, and third tubular members. The depicted tubularmembers include an inner tubular member 20 a, an intermediate tubularmember 20 b, and a rotatable outer tubular member 20 c. In theembodiment depicted in figures, the inner tubular member 20 a andintermediate tubular member 20 b are axially affixed to one another at adistal position 136 distally located from the articulable portion 8.However, the rotatable outer tubular member 20 c may, or may not, beaxially affixed to either of the other tubular members depending on theparticular embodiment. In the depicted embodiment, the inner tubularmember 20 a may be biased relative to the intermediate tubular member 20b to articulate the articulable portion 8 of the surgical instrument.Additionally, as described in more detail below, the outer tubularmember 20 c may be rotated relative to the other tubular members toprevent articulation of the articulable portion 8.

FIGS. 3A-5A present side views of the various tubular members that arerotated 90° between the paired figures to better visualize the flexibleportions of the tubular members.

FIGS. 3A and 3B depict side and bottom views of the flexible portion ofthe inner tubular member 20 a. The flexible portion of the inner tubularmember 20 a includes a single spine 100 extending along one side of thetubular member. The spine 100 corresponds to a continuous portion of thetubular member capable of transmitting axial forces along the length ofthe tubular member. The spine 100 may be defined by a series of slots102 formed in the inner tubular member 20 a. The spine 100 and the slots102 may interact to form a plurality of flexible segments 104 joinedtogether by a plurality of living hinges 106. The adjacent flexiblesegments 104 may be pivoted relative to one another about theintervening living hinges 106. It is this relative pivoting of theindividual flexible segments 104 that imparts flexibility to the innertubular member 20 a. In addition, it is the orientation of the spine 100and the slots 102 that define the preferential bending direction 124about an axis of rotation of the living hinges 106. Without wishing tobe bound by theory, the living hinges 106 exhibit increased bendingresistance in directions other than those corresponding to pivoting ofthe living hinges 106 about the axes of rotation of the living hinges106. Thus, directions in which the living hinges 106 exhibit increasedstiffness may be viewed as corresponding to directions of bendingresistance. In the depicted embodiment, a direction of bendingresistance 126 may correspond to a direction that is perpendicular tothe preferential bending direction and parallel to the axes of rotationof the living hinges 106 of the inner tubular member 20 a.

FIGS. 4A and 4B depict side and bottom views of the intermediate tubularmember 20 b. The intermediate tubular member 20 b may be sized andshaped to accommodate the inner tubular member 20 a when they arecoaxially disposed in the assembled elongated shaft assembly. Similar tothe above, the intermediate tubular member 20 b may include a flexibleportion defined by a plurality of slots 110 formed in the tubularmember. However, in contrast to the inner tubular member, the depictedembodiment of the intermediate tubular member 20 b includes two spines108 that are defined by the slots 110 arranged on both sides of the twospines. In the depicted embodiment, the spines 108 extend distally alongthe flexible portion of the tubular member and are arranged on oppositesides of the tubular member, though other arrangements of the spinesrelative to one another are also possible. The depicted arrangement ofthe spines 108 and the slots 110 results in two separate sets ofadjacent flexible segments 112 located above and below the spines 108.Each of the flexible segments 112 are pivotable about living hinges 114formed between the junctions of the spines 108 and the slots 110. Insome embodiments, and as depicted in the figures, each slot 110 may beassociated with one or more secondary slots 111. The depicted secondaryslots 111 are horizontally arranged slots located at the ends of theslots 110. Without wishing to be bound by theory, the secondary slots111 may reduce the amount of material corresponding to the living hinges114 which may impart greater flexibility to the flexible segments 112for a given articulation force. While the secondary slots have beendepicted as being horizontal slots located at the junction between thespines and flexible segments, other arrangements are also possible.

Without wishing to be bound by theory, due to the inclusion of twospines 108 located on opposite sides of the intermediate tubular member,the preferential bending direction and direction of bending resistanceare different than that described above with regards to inner tubularmember 20 a. More specifically, the inclusion of the two spines 108results in the living hinges 114 having axes of rotation that areoriented perpendicular to the spines in a direction that is parallel toa plane extending between the spines 108 (i.e. the axes of rotationextend between the two opposing spines). In addition, due to thesymmetry of the slot patterns on either side of the spines, the livinghinges 114 located above and below the spines 108 have axes of rotationthat are aligned with one another. Consequently, the individual flexiblesegments 112, and the overall flexible portion of the intermediatetubular member 20 b, exhibit a preferential bending direction 128 thatcorresponds to a direction of rotation around the living hinges 114which is perpendicular to the plane extending between the spines 108.

Due to the individual flexible segments 112 of the intermediate tubularmember 20 b being associated with two spines 108 on either side of thetubular member, the intermediate tubular member 20 b also exhibitsdirections of increased bending resistance that are different thandescribed above with regards to the inner tubular member 20 a. Withoutwishing to be bound by theory, the intermediate tubular member 20 bexhibits an increased bending resistance in a direction that is parallelto the plane extending between the two spines. The observed increase inbending resistance may be due to the spines on either side of thetubular member resisting extension and contraction of the tubular memberas might occur during bending of the tubular member in a direction thatis parallel to the plane extending between the two spines. Further, eachof the flexible segments 112 are connected to both of the spines 108 oneither side of the tubular member. Thus the movement of the two spines108 relative to one another may be further limited since the spines arein effect fixed to one another at points extending along their lengthswhich may lead to an additional increase in the resistance to bending ofthe tubular member. This behavior may be contrasted with the flexiblesegments 112 and slots 110 which are specifically configured toaccommodate both extension and contraction of the tubular member tofacilitate bending of the elongated shaft assembly. In view of theabove, the inclusion of the two spines 108 in the intermediate tubularmember 20 b results in a direction of increased bending resistance 130that is perpendicular to the preferential bending direction 128 and thedirection of rotation of the living hinges 114. Additionally thedirection of increased bending resistance 130 may also be parallel tothe plane extending between the two spines 108 as well as axes ofrotation for the living hinges 114.

FIGS. 5A and 5B depict the outer tubular member 20 c which may be sizedand shaped to accommodate the inner tubular member 20 a and theintermediate tubular member 20 b when they are coaxially disposed withinthe elongated shaft assembly 6. In addition, the depicted embodiment ofthe outer tubular member 20 c may exhibit a similar arrangement ofspines 116, slots 118, flexible segments 120, and living hinges 122 asdescribed above with regards to the intermediate tubular member 20 b.Consequently, similar to the intermediate tubular member 20 b, the outertubular member 20 c may exhibit a preferential bending direction 132that corresponds to a direction of rotation around the living hinges 122and is perpendicular to a plane extending between the spines 116.Additionally, the outer tubular member 20 c may exhibit a direction ofincreased bending resistance 134 which is perpendicular to thepreferential bending direction 132. The direction of increased bendingresistance 134 may also be parallel to the plane extending between thetwo spines 116 and the axes of rotation of the living hinges 122.

FIGS. 6A-7B depict one embodiment of how the elongated shaft assembly 6may be articulated. For the sake of clarity in illustrating how theelongated shaft assembly is articulated, only the inner tubular member20 a and the intermediate tubular 20 b are depicted in the figures.

In the depicted embodiment, the inner tubular member 20 a may becoaxially disposed within the intermediate tubular member 20 b. Theflexible portions of the tubular members 20 a and 20 b may be aligned toform articulable portion 8. Further, the tubular members 20 a and 20 bmay be axially affixed to one another at the distal position 136 whichis distally located relative to the articulable portion 8. The tubularmembers may be affixed to one another using welding, brazing, soldering,adhesives, mechanical interlocking features, or any other appropriatemethod capable of affixing the tubular members to one another. It shouldbe noted, that while the tubular members 20 a and 20 b may be axiallyaffixed to one another at a distal position 136, the tubular members 20a and 20 b may be free to move relative to one another at their proximalends. As depicted in figures, the tubular members 20 a and 20 b may alsoinclude retaining elements 126 and 128 to interact with componentswithin the handle to bias the inner tubular member 20 a relative to theintermediate tubular member 20 b.

FIG. 6A depicts the tubular members 20 a and 20 b in the unbiasedposition in which neither tubular member is under compression ortension. When a user wishes to articulate articulable portion 8, innertubular member 20 a may be distally displaced relative to theintermediate tubular member 20 b by a force F, see FIG. 6B. Dependingupon the particular embodiment, a force directed in the distal directionmay result in articulation in a first direction and a force directed inthe proximal direction may result in articulation in a second directionopposite from the first. Without wishing to be bound by theory, as theinner tubular member 20 a is displaced relative to the intermediatetubular member 20 b, a compressive or tensile force is created in theinner tubular member 20 a and a corresponding tensile or compressiveforce is created in the intermediate tubular member 20 b depending onthe direction of the relative displacement. It is the interaction of thecompressive and tensile forces with the flexible portions of the tubularmembers that results in the articulation depicted in FIG. 6B.

FIGS. 7A-7B present an external perspective view, as well as across-sectional view, of the articulable portion 8 formed by the innertubular member 20 a and the intermediate tubular member 20 b to betterillustrate how the articulation motion is created by biasing the innertubular member 20 a relative to the intermediate tubular member 20 b. Asnoted previously, the inner tubular member 20 a and the intermediatetubular member 20 b are axially affixed to one another at a distalposition 136, but are free to move relative to one another at positionsproximal to the distal position 136. Without wishing to be bound bytheory, when a force is applied to one of the tubular members acompressive force is applied to one tubular member and a tensile forceis applied to the other tubular member. It should be noted that theflexible segments 104 and 112 of the tubular members of the depictedembodiment do not carry the compressive and tensile loads applied to thetubular members since each flexible segment 104 and 112 is free to moverelative to the other adjacent flexible segments. Instead, the spines100 and 108 carry the compressive and tensile loads applied to thetubular members 20 a and 20 b. In addition to carrying the compressiveand tensile loads, the spines 100 and 108 tubular members remain thesame length when a biasing force is applied for the reasons notedpreviously. In contrast, the flexible segments 104 and 112 of thetubular members may expand and contract relative to one another when abiasing force is applied.

As best illustrated by FIG. 7B, and without wishing to be bound bytheory, when a force is applied to the inner tubular member 20 a, thespine 100 applies the force to one side of the elongated shaft assemblyat the distal position 136 where the tubular members 20 a and 20 b areaxially affixed to one another. A corresponding force is applied to theelongated shaft assembly by the spines 108 of the intermediate tubularmember 20 b which are spaced from the spine 100 of the inner tubularmember 20 a. This application of spaced apart forces from the spine 100and the spines 108 creates a bending moment in the elongated shaftassembly 6 resulting in compression of the flexible segments 104 and 112of the tubular members on one side of the articulable portion 8. Sincethe spines 100 and 108 stay the same size while the flexible segments104 and 112 pivot to accommodate the applied bending moment, articulableportion 8 articulates. It should be noted, that if a force is applied tothe inner tubular member in the opposite direction, the flexiblesegments 104 and 112 would expand on one side of the articulable portion8 to articulate the elongated shaft assembly 6 in the oppositedirection.

In addition to looking at how the spines of the tubular members carrythe applied forces to articulate the articulable portion 8, thearticulation of articulable portion 8 may also be described using theneutral bending axes of the tubular members relative to one another.Without wishing to be bound by theory, when an axially oriented force isapplied to an object, the force may be approximated as a force appliedalong the neutral bending axis. Within the articulable portion 8, theneutral bending axis 138 of the inner tubular member 20 a corresponds tothe spine 100. In contrast, due to the inclusion of the two distallyextending spines 108 located on opposite sides of the intermediatetubular member 20 b, intermediate tubular member 20 b has a neutralbending axis 140 that corresponds to the central axis of theintermediate tubular member 20 b. Thus, a biasing force applied to oneof the tubular members may result in equal and opposite forces beingapplied along the two offset neutral bending axes. The forces applied tothe tubular members along the offset neutral bending axes may againcreate a bending moment within the elongated shaft assembly 6 toarticulate the articulable portion 8 as described above.

It should be understood that while tubular members with particularpatterns of slots and spines have been depicted in the figures anddescribed herein, other arrangements of tubular members with differentpatterns of slots and spines as well as different numbers of spines arealso possible to provide the desired articulation of the surgicalinstrument. Further, other types of articulation may be incorporatedinto the surgical instrument as the current disclosure is not limited toany particular form of articulation control or any particular form ofarticulation.

Turning now to how an articulation locking mechanism might operate,FIGS. 8-11 depict the elongated shaft assembly 6 with the rotatableouter tubular member 20 c which may be rotated between an articulableconfiguration and a non-articulable configuration.

FIGS. 8-9 depict an exploded schematic view, as well as across-sectional view, of the elongated shaft assembly 6 in thearticulable configuration. In the depicted embodiment, the inner tubularmember 20 a is disposed within the intermediate tubular member 20 bwhich is disposed within the outer tubular member 20 c. In the depictedconfiguration, the preferential bending directions 124, 128, and 132 ofeach of the tubular members 20 a-20 c are aligned with one another.Correspondingly, the spine 100 of inner tubular member 20 a isperpendicular to the spines 108 of the intermediate tubular member 20 band the spines 116 of the outer tubular member 20 c. In the depictedembodiment, the articulation direction of the elongated shaft assembly 6may correspond to the preferential bending direction 124 of the innertubular member 20 a. Consequently, the preferential bending direction132 of the outer tubular member 20 c is aligned with the articulationdirection of the elongated shaft assembly 6. Since the preferentialbending directions of each of the tubular members are aligned with oneanother as well as being aligned with the articulation direction of theelongated shaft assembly 6, the elongated shaft assembly 6 may bearticulated when it is biased by the associated articulation control.

When it is desired to prevent articulation of the elongated shaftassembly 6, outer tubular member 20 c may be rotated relative to theinner tubular member 20 a and intermediate tubular member 20 b to thenon-articulable configuration as depicted in FIGS. 10-11. While thisrotation may be of any appropriate angle, in the depicted embodiment theouter tubular member 20 c is rotated approximately 90° between thearticulable configuration and the non-articulable configuration. Asillustrated in the figures, the preferential bending directions 124 and128 of the inner tubular member 20 a and the intermediate tubular member20 b remain aligned for the purposes of articulation. However, thepreferential bending direction 132 of the outer tubular member 20 c isno longer aligned with the preferential bending directions 124 and 128.Instead, the direction of bending resistance 134 of the outer tubularmember 20 c is aligned with the preferential pending directions 124 and128. Further, the spine 100 of the inner tubular member 20 a isperpendicular to the spines 108 of the intermediate tubular member 20 band aligned with the spines 116 of the outer tubular member 20 c. Asnoted above, the articulation direction of the elongated shaft assembly6 may correspond to the preferential bending direction 124 the innertubular member 20 a. Consequently, the direction of bending resistance134 is aligned with the articulation direction of the elongated shaftassembly 6 in the depicted embodiment. Due to the direction of bendingresistance 134 of the outer tubular member 20 c being aligned with thearticulation direction, as well as the preferential bending directionsof the other tubular members 20 a and 20 b, the outer tubular member 20c may prevent articulation of the elongated shaft assembly in thedepicted configuration.

It should be understood that while a particular arrangement of spinesand slots have been described above with regards to the tubular membersto provide the desired preferential bending directions and directions ofbending resistance, the current disclosure is not limited to only thedepicted tubular members. For example, in addition to use with tubularmembers including a pattern of slots and spines, the current disclosuremay be used with tubular members including flexible sections comprisedof individual articulating links that are constructed and arranged to bedisplaceable in one or more preselected directions. Consequently, thecurrent disclosure should be viewed generally as applying to thearticulation of any device including any appropriately adapted componentthat is capable of being moved to selectively align a preferentialbending direction and a direction of bending resistance with anarticulable portion of the device to selectively permit or preventarticulation of the device.

The above embodiments have depicted the tubular member used toselectively prevent articulation of the surgical instrument as beinglocated at the exterior of the elongated shaft assembly. However, thecurrent disclosure is not limited as to the particular position of thetubular member. For example, the elongated shaft assembly may include atubular member to selectively prevent articulation that is arranged asan interior tubular member, an intermediate tubular member, or anexterior tubular member.

In some embodiments, it may be advantageous to provide an elongatedshaft assembly that may be articulated and selectively prevented fromarticulating using two tubular members instead of the three tubularmembers as disclosed above. In such an embodiment, the tubular membersmay be constructed and arranged to provide a similar functionality asdescribed above with regards to the inner tubular member and theintermediate tubular member to articulate the elongated shaft assembly.In addition, similar to the embodiment described above, the tubularmembers may be axially affixed to one another at a distal position tofacilitate articulation of the elongated shaft assembly. However, inaddition to being axially affixed to one another to facilitatearticulation of the elongated shaft assembly, the tubular members mayalso be rotatable relative to one another to selectively permit orprevent articulation of the elongated shaft assembly. Similar to theabove described embodiments, the elongated shaft assembly might bearticulable when the preferential bending directions of the tubularmembers are aligned with one another. Further, the elongated shaftassembly may be prevented from articulating when a direction of bendingresistance of one tubular member is aligned with the preferentialbending direction of the other tubular member and/or the articulationdirection of the elongated shaft assembly 6.

The two tubular members of the above embodiment may be rotatably coupledwhile being axially affixed to one another at a distal position usingany appropriate connection. For example, in one embodiment, the tubularmembers may include a boss and a corresponding shelf that would axiallyconstrain the tubular members relative to one another while permittingrotation. In another embodiment, the tubular members may includeinterlocking mechanical elements that axially constrain the tubularmembers while permitting rotation of the tubular members relative to oneanother. One example of such an embodiment may include a tubular memberwith a lip at a distal end that is captured by a corresponding featureon the other tubular member. It should be understood that otherconfigurations are possible and that the current disclosure is notlimited to only the rotatable couplings noted above. In addition, insome embodiments, it may be desirable to decrease the friction presentwithin the rotatable coupling to aid in the rotation of the tubularmembers relative to one another. Consequently, it may be advantageous toinclude features to facilitate the rotation of the tubular membersrelative to another such as lubrication, bearings, low frictionmaterials, and other appropriate features.

In some embodiments, it may be desirable to provide a differentconfiguration or pattern of slots and spines on one or more of thetubular members. Different arrangements of slots and spines on thetubular members may provide benefits including different articulationcharacteristics, reduced interference between moving components,increased bending resistance in selected directions, decreased bendingresistance in selected directions, increased articulation ranges,complex articulation directions and other benefits as would be obviousto one of ordinary skill in the art. The different configurations andpatterns of the slots and spines may include helically arranged slots,slanted slots, a plurality of distally extending spinescircumferentially arranged around the tubular members, spines orientedat an angle relative to the tubular member axis, and any otherappropriate pattern or arrangement as the current disclosure is notlimited to any particular construction. In addition, the tubular membersmay be formed using laser cutting, grinding, water cutting, milling, orany other appropriate method.

Without wishing to be bound by theory, large articulation angles of thetubular members may result in contact between adjacent flexible segmentswhich may prevent additional articulation of the elongated shaftassembly. However in some embodiments, large articulation angles may bedesirable for a particular use. Consequently, in some embodiments, largearticulation angles may be accommodated by providing longer articulableportions capable of articulating to larger angles while maintaining thesame angular displacement per flexible segment. Alternatively, in someembodiments, the maximum angular displacement per flexible segment maybe increased to accommodate the large articulation angle. The maximumangular displacement per flexible segment may be increased by increasinga width of the slots, or by including reliefs or cutouts on the flexiblesegments to increase the angle at which contact occurs between adjacentflexible segments. Combinations of the above embodiments may also beused (e.g., a longer articulable portion and reliefs formed on theflexible segments). While the above embodiments are directed toincreasing the permissible articulation angle, in some embodiments, itmay be desirable to limit the articulation angle of the elongated shaftassembly. In such an embodiment, the length of the articulable portionand/or the maximum angular displacement per flexible segment may beselected to provide a desired maximum articulation angle.

In some embodiments, and as noted above, it may be desirable toarticulate the surgical instrument in more than one direction. Forexample, it may be desirable to articulate the surgical instrument in avertical direction, a horizontal direction, or a direction between thevertical and horizontal directions. These complex articulations may beprovided in any number of ways. For example, in one embodiment, three ormore tubular members including appropriately oriented spines and slotsmight be used to provide articulation in multiple directions.Alternatively, a flexible tubular member may include appropriatearticulation mechanisms such as wires or slats capable of articulatingthe tubular member in multiple directions. In addition to articulatingthe surgical instrument in multiple directions, it may also be desirableto selectively permit or prevent the articulation of the surgicalinstrument in one, or all, of the articulable directions. In such anembodiment, one or more tubular members may be used to permit or preventthe articulation of the surgical instrument in any one, or all, of thearticulation directions. For example, a single tubular member mayinclude a plurality of preferential bending directions as well as aplurality of directions of bending resistance which may be selectivelyaligned with the plurality of articulation directions to selectivelypermit or prevent articulation of the surgical instrument in one, or allof the articulable directions. Alternatively, a plurality of tubularmembers each including a preferential bending direction and a directionof bending resistance might be used. In such an embodiment, each of theplurality of tubular members may be oriented to selectively permit orprevent articulation of the surgical instrument in a particulardirection. Other configurations using a plurality of tubular members arealso possible.

FIG. 12 depicts the elongated shaft assembly 6 including the innertubular member, the intermediate tubular member, and the outer tubularmember, as described above, incorporated in a surgical instrument 2. Inthe depicted embodiment, the elongated shaft assembly 6 extends distallyfrom the handle 4 and is associated with an articulation control 10.More specifically, articulation control 10 is a rotatable component thatincludes a slot 202. The slot 202 is sized and shaped to interact with acorresponding pin 204 associated with an articulation coupling 200. Thearticulation coupling 200 is coupled to the elongated shaft assembly 6to control the articulation of the articulable portion 8 depicted inFIG. 1 by selectively displacing one of the inner tubular member and theintermediate tubular member as noted above. More specifically, as thearticulation control 10 is rotated, the pin 204, the articulationcoupling 200, and the associated tubular member are selectively moved ineither a proximal or distal direction to articulate, or straighten, thearticulable portion 8.

In some instances, and as depicted in the figure, the slot 202 may beshaped to provide two resting positions for pin 204. These positions maycorrespond to the unarticulated position and the fully articulatedposition of articulable portion 8. In other embodiments, the slot 202may be shaped and arranged to include more than two resting positions toprovide multiple articulated positions of articulable portion 8.Alternatively, the slot 202 may provide a gradual transition between theunarticulated and fully articulated position. In such an embodiment, thearticulation control 10 may include a locking mechanism or havesufficient friction to maintain the pin 204, and correspondingly thearticulable portion 8, at any desired articulation angle between theunarticulated and fully articulated position. Additionally, as notedabove, in some instances it may be desirable to provide articulation intwo directions (i.e. up and down). In such an embodiment, the slot 202may be shaped and arranged to include a first resting positioncorresponding to the unarticulated position as well as one or moreresting positions on either side of that first resting position toenable articulation of the articulable portion 8 in both directions.

While a specific articulation control and articulation coupling havebeen depicted in the figures and described herein, the currentdisclosure is not limited to only the depicted embodiments. Therefore,it should be understood that any appropriate articulation coupling andarticulation control could be used. Further, any appropriate method fortransferring movement of the articulation control to the articulationcoupling and/or articulable portion 8 could also be used. Thearticulation control may also be moved between the various articulationpositions using any appropriate motion including linear movement in aproximal and distal direction, linear movement in the verticaldirection, linear movement in the horizontal direction, rotation in aproximal or distal direction, rotation in the vertical direction, and/orrotation in the horizontal direction. Combinations of the abovemovements, as well as other types of movements, to move the articulationcontrol between two or more positions are also possible.

In order to control the rotation of the outer tubular member 20 c toselectively permit or prevent articulation of the surgical instrument,the handle 4 may include a rotatable collar 205 associated with theouter tubular member 20 c. In the depicted embodiment, rotation of therotatable collar 205 directly rotates the outer tubular member 20 crelative to the articulable portion 8 of the elongated shaft assembly toselectively move the preferential bending direction of the outer tubularmember 20 c into and out of alignment with the articulation direction ofthe elongated shaft assembly 6. Consequently, rotation of the rotatablecollar 205, and the associated outer tubular member 20 c, mayselectively permit, or prevent, articulation of the elongated shaftassembly 6. In some embodiments, the rotatable collar 205 may only berotatable between an articulable position and a non-articulableposition. Alternatively, the rotatable collar 205 may be positioned atany number of distinct positions between the articulable position andthe non-articulable position to provide partial locking of thearticulable portion of the elongated shaft assembly. To facilitatepositioning of the rotatable collar 205, the rotatable collar 205 mayinclude detent mechanisms, or any other appropriate feature, tofacilitate the positioning and retention of the outer tubular member 20c in any number of preselected positions. However, embodiments notincluding a detent mechanism, or other appropriate feature to controlthe position of the outer tubular member 20 c, are also envisioned.Further, while a particular rotatable collar has been depicted forcontrolling the positioning of the outer tubular member 20 c, anyappropriate construction capable of positioning the outer tubular member20 c in the desired orientation might be used. For example, both directcouplings such as the depicted rotatable collar as well as indirectcouplings including transmissions might be used to move the outertubular member 20 c between the articulable position and thenon-articulable position.

As noted previously, the surgical instrument 2 may also include afastener deployment system as depicted in FIG. 12. The fastenerdeployment system 102 may be embodied in a number of different ways.However, in the particular embodiment depicted in FIG. 12 the fastenerdeployment system may include a trigger 14, a rigid linkage 206, ashuttle 208, a power assist device 210, and a driveshaft 212 as well asother components that are not depicted. When the surgical instrument 2is actuated, actuation of the trigger 14 may distally displace the rigidlinkage 206 to distally displace the shuttle 208 and store energy in thepower assist device 210. After a preselected amount of actuation, thepower assist device 210 may release the stored energy to distallyaccelerate driveshaft 212 and deploy a fastener from the distal end ofthe elongated shaft assembly 6.

The power assist device 210 may correspond to any appropriateconstruction capable of aiding in deploying a fastener from theelongated shaft assembly of the surgical instrument. Further, dependingon the particular embodiment, the power assist device 210 may supply allof the power necessary to deploy a fastener, or it may only supply aportion of the power necessary to deploy a fastener. In one specificembodiment, the power assist device 106 corresponds to the power assistdevice disclosed in application Ser. No. 13/804,043 entitled POWERASSIST DEVICE FOR A SURGICAL INSTRUMENT filed on the same day as thecurrent application. While a surgical instrument including a powerassist device has been depicted, in some embodiments, the surgicalinstrument 2 may not include a power assist device, in which caseactuation of the trigger 14 may directly, or indirectly, displacedriveshaft 212 to deploy a fastener from a distal end of the elongatedshaft assembly 6.

While the present teachings have been described in conjunction withvarious embodiments and examples, it is not intended that the presentteachings be limited to such embodiments or examples. On the contrary,the present teachings encompass various alternatives, modifications, andequivalents, as will be appreciated by those of skill in the art.Accordingly, the foregoing description and drawings are by way ofexample only.

What is claimed is: 1-30. (canceled)
 31. A method of operating asurgical instrument, the method comprising: displacing a first tubularmember of an elongated shaft assembly, the first tubular memberincluding a flexible portion with a preferential bending direction and adirection of bending resistance to selectively align the preferentialbending direction of the first tubular member with an articulationdirection of the an articulable portion of the elongated shaft assembly,wherein aligning the preferential bending direction of the first tubularmember with the articulation direction of the articulable portion topermits articulation of the elongated shaft assembly.
 32. The method ofclaim 31, further comprising displacing the first tubular member toselectively align the direction of bending resistance with thearticulation direction of the elongated shaft assembly to preventarticulation of the elongated shaft assembly.
 33. The method of claim31, wherein displacing the first tubular member comprises rotating thetubular member.
 34. The method of claim 33, wherein rotating the firsttubular member comprises rotating the tubular member by 90°.
 35. Themethod of claim 31, wherein the direction of bending resistance isparallel to a plane extending between a first spine and a second spinelocated on opposite sides of the first tubular member, and displacingthe first tubular member includes aligning the plane with thearticulation direction of the elongated shaft assembly.
 36. The methodof claim 31, further comprising axially displacing at least a portion ofthe elongated shaft assembly relative to a distal end of the firsttubular member.
 37. The method of claim 31, wherein displacing the firsttubular member further comprising aligning the preferential bendingdirection of the first tubular member with at least one of apreferential bending direction of a second tubular member and apreferential bending direction of a third tubular member within theelongated shaft assembly to permit articulation of the elongated shaftassembly.
 38. The method of claim 37, further comprising displacing thefirst tubular member to align the direction of bending resistance withat least one of the preferential bending direction of the second tubularmember and the preferential bending direction of the third tubularmember to prevent articulation of the elongated shaft assembly.
 39. Themethod of claim 37, further comprising axially displacing a proximal endof the second tubular member relative to a proximal end of the thirdtubular member to articulate the elongated shaft.
 40. A method ofoperating a surgical instrument, the method comprising: rotating a firsttubular member of an articulable elongated shaft assembly including anarticulable portion to selectively prevent articulation of thearticulable portion of the elongated shaft assembly, wherein the firsttubular member includes a first flexible portion with a first spine anda second spine that at least partially overlap the flexible portion ofthe elongated shaft assembly.
 41. The method of claim 40, whereinrotating the first tubular member includes aligning the first and secondspines with an articulation direction of the articulable portion of theelongated shaft assembly to selectively prevent articulation of thearticulable portion of the elongated shaft assembly.
 42. The method ofclaim 41, wherein the elongated shaft assembly includes a second tubularmember including a second flexible portion with a third spine, andwherein rotating the first tubular member includes aligning the firstand second spines with the third spine to selectively preventarticulation of the articulable portion of the elongated shaft assembly.43. The method of claim 42, further comprising axially displacing aproximal end of the first tubular member relative to a proximal end ofthe second tubular member to articulate the articulable portion of theelongated shaft assembly.
 44. The method of claim 43, further comprisingpreventing relative axial movement of the first and second tubularmembers at a position distal from the first and second flexibleportions.
 45. The method of claim 42, wherein rotating the first tubularmember rotates the first tubular member relative to a third tubularmember of the elongated shaft assembly including a third flexibleportion with a fourth spine.
 46. The method of claim 45, furthercomprising axially displacing a proximal end of the second tubularmember relative to a proximal end of the third tubular member toarticulate the articulable portion of the elongated shaft assembly. 47.The method of claim 46, further comprising preventing relative axialmovement of the second and third tubular members at a position distalfrom second and third flexible portions.
 48. The method of claim 46,wherein the third tubular member includes a fifth spine, and wherein thefourth spine and the fifth spine are perpendicular to the first spine topermit articulation of the articulable portion of the elongated shaftassembly.
 49. The method of claim 48, wherein rotating the first tubularmember includes aligning the first and second spines with the fourth andfifth spines to selectively permit articulation of the articulableportion of the elongated shaft assembly.
 50. A method of operating asurgical instrument, the method comprising: rotating a tubular member ofan elongated shaft assembly between an articulable configuration and anon-articulable configuration to selectively permit or preventarticulation of the elongated shaft assembly.
 51. The method of claim50, wherein rotating the tubular member between the articulableconfiguration and the non-articulable configuration further comprisesselectively aligning a direction of bending resistance and apreferential bending direction of the tubular member with anarticulation direction of the elongated shaft assembly to selectivelypermit or prevent articulation of the elongated shaft assembly.
 52. Themethod of claim 51, wherein the direction of the bending resistance isdefined by a plane extending between a first spine and a second spineformed in a flexible portion of the tubular member.
 53. The method ofclaim 52, wherein the first spine and the second spine are formed onopposing sides of the flexible portion of the tubular member.